Coseismic deformation, field observations and seismic fault of the 17 November 2015 M = 6.5, Lefkada Island, Greece earthquake

2016 ◽  
Vol 687 ◽  
pp. 210-222 ◽  
Author(s):  
Athanassios Ganas ◽  
Panagiotis Elias ◽  
George Bozionelos ◽  
George Papathanassiou ◽  
Antonio Avallone ◽  
...  
Keyword(s):  
Deformation Field ◽  
Coseismic Deformation ◽  
Field Observations ◽  
Seismic Fault ◽  
Lefkada Island

scholarly journals COSEISMIC DEFORMATION AND SEISMIC FAULT OF THE 17 NOVEMBER 2015 M=6.5 EARTHQUAKE, LEFKADA ISLAND

2017 ◽  
Vol 50 (1) ◽  
pp. 491 ◽  
Author(s):  
Ath. Ganas ◽  
P. Briole ◽  
D. Melgar ◽  
G. Bozionelos ◽  
S. Valkaniotis ◽  
...  
Keyword(s):  
Plate Boundary ◽  
Strong Support ◽  
Vertical Motion ◽  
Coseismic Deformation ◽  
Western Coast ◽  
Coseismic Slip ◽  
Seismic Fault ◽  
Image Pairs ◽  
Lefkada Island ◽  
Continuous Gps

On November 17, 2015 a strong, shallow earthquake, Mw 6.5, occurred on the island of Lefkada along a strike-slip fault with right-lateral sense of slip. The event triggered widespread environmental effects that were mainly reported at the south and western part of the island while moving towards the eastern part, the intensity and severity of these earthquake-induced deformations were decreased. Relocation of seismicity and inversion of geodetic data suggests that the seismic fault runs parallel to the west coast of Lefkada, along the Aegean - Apulia plate boundary. The earthquake measured Mw=6.5 using the PGD relation of Melgar et al (2015, GRL). The fault plane strikes N20±5°E and dips to east with an angle of about 70±5 degrees. Coseismic deformation was measured in the order of tens of centimeters of horizontal motion by continuous GPS stations of NOANET (the NOA GPS network) and by InSAR (Sentinel 1A image pairs). Released interferograms from various groups show a large decorrelation area that extends almost along all the western coast of Lefkada, observation which provides strong support of landsliding. A coseismic slip model was produced from inversion of the ascending InSAR. We have not observed significant vertical motion of the shoreline and this is consistent with the predictions of the model.

scholarly journals Co-seismic and post-seismic deformation, field observations and fault model of the 30 October 2020 Mw = 7.0 Samos earthquake, Aegean Sea

2021 ◽  
Author(s):  
Athanassios Ganas ◽  
Panagiotis Elias ◽  
Pierre Briole ◽  
Sotiris Valkaniotis ◽  
Javier Escartin ◽  
...  
Keyword(s):  
Aegean Sea ◽  
Fault Model ◽  
Deformation Field ◽  
Field Observations ◽  
Seismic Deformation

scholarly journals Coseismic Deformation and Speculative Seismogenic Fault of the 2017 MS 6.6 Jinghe Earthquake, China, Derived From Sentinel-1 Data

2021 ◽  
Vol 9 ◽  
Author(s):  
Wei Feng ◽  
Zechao Bai ◽  
Jinwei Ren ◽  
Shuaitang Huang ◽  
Lin Zhu
Keyword(s):  
European Space Agency ◽  
Image Data ◽  
Junggar Basin ◽  
Deformation Field ◽  
Slip Distribution ◽  
Coseismic Deformation ◽  
Dislocation Model ◽  
Seismogenic Fault ◽  
Geological Investigation ◽  
Maximum Deformation

A MS 6.6 earthquake struck Jinghe County in Bortala Mongol Autonomous Prefecture of Xinjiang Uygur Autonomous Region on August 9, 2017. The earthquake occurred near the eastern part of the Kusongmuxieke Piedmont Fault (KPF) in the southwest of Junggar Basin. Using two pairs of coseismic SAR image data from the ascending and descending tracks from Sentinel-1 (European Space Agency), we processed the interferograms to obtain the coseismic deformation field. We calculate the fault slip distribution of the earthquake based on the elastic half-space rectangular dislocation model with the available location, geometry from seismic data and the coseismic deformation data. The results show that the earthquake deformation field has the typical characteristics of thrust faulting. The uplift deformation field is about 28 km long and 20 km wide. The maximum displacements of InSAR line-of-sight to the ascending and descending tracks are 49 and 68 mm, respectively. The main slip is concentrated at the depth of 10–20 km. The inverted seismic moment is equivalent to a moment magnitude MW 6.3. This result is very similar to the slip distribution from the seismological inversion. The maximum deformation area and the distribution of aftershocks are both on the west side of the mainshock. They mutually confirm the characteristics of a unilateral rupture. According to stress triggering theory, the aftershocks within 1 month after the mainshock in the layer 10–14 km deep may have been triggered by the mainshock, and the transferred stress increases the seismic risk of the eastern section of the KPF fault. After more than 1 year, a MS 5.4 earthquake occurred to the southwest of the MS 6.6 Jinghe earthquake. Beacause the stress drop change (<0.01 MPa) is too small for the MS 5.4 earthquake to have been directly triggered. Based on the analysis of multisource data and the detailed geological investigation, the thrust Jinghenan fault which north of Kusongmuxieke Piedmont fault is inferred to be the seismogenic fault of the MS 6.6 Jinghe earthquake.

scholarly journals COSEISMIC DEFORMATION FIELD AND FAULT SLIP DISTRIBUTION OF THE 2015 CHILE Mw8.3 EARTHQUAKE

2016 ◽  
Vol XLI-B7 ◽  
pp. 827-834
Author(s):  
Chunyan Qu ◽  
Ronghu Zuo ◽  
Xin Jian Shan ◽  
Guohong Zhang ◽  
Yingfeng Zhang ◽  
...  
Keyword(s):  
Elastic Half Space ◽  
Fault Slip ◽  
Deformation Field ◽  
Coseismic Deformation ◽  
Postseismic Deformation ◽  
Coseismic Slip ◽  
Single Plane ◽  
Rupture Length ◽  
Continental Plate ◽  
Before And After

On September 16, 2015, a magnitude 8.3 earthquake struck west of Illapel, Chile. We analyzed Sentinel-1A/IW InSAR data on the descending track acquired before and after the Chile Mw8.3 earthquake of 16 September 2015. We found that the coseismic deformation field of this event consists of many semi circular fringes protruding to east in an approximately 300km long and 190km wide region. The maximum coseismic displacement is about 1.33m in LOS direction corresponding to subsidence or westward shift of the ground. We inverted the coseismic fault slip based on a small-dip single plane fault model in a homogeneous elastic half space. The inverted coseismic slip mainly concentrates at shallow depth above the hypocenter with a symmetry shape. The rupture length along strike is about 340 km with maximum slip of about 8.16m near the trench. The estimated moment is 3.126×1021 N.m (Mw8.27)，the maximum depth of coseismic slip near zero appears to 50km. We also analyzed the postseismic deformation fields using four interferograms with different time intervals. The results show that postseismic deformation occurred in a narrow area of approximately 65km wide with maximum slip 11cm, and its predominant motion changes from uplift to subsidence with time. that is to say, at first, the postseismic deformation direction is opposite to that of coseismic deformation, then it tends to be consistent with coseismic deformation.It maybe indicates the differences and changes in the velocity between the Nazca oceanic plate and the South American continental plate.

scholarly journals InSAR 3-D Coseismic Displacement Field of the 2015 Mw 7.8 Nepal Earthquake: Insights into Complex Fault Kinematics during the Event

2020 ◽  
Vol 12 (23) ◽  
pp. 3982
Author(s):  
Chunyan Qu ◽  
Xin Qiao ◽  
Xinjian Shan ◽  
Dezheng Zhao ◽  
Lei Zhao ◽  
...  
Keyword(s):  
Surface Deformation ◽  
Three Dimensional ◽  
Deformation Field ◽  
Coseismic Deformation ◽  
Maximum Displacement ◽  
Nepal Earthquake ◽  
The North ◽  
Complex Fault ◽  
Fault Kinematics ◽  
East West

The 2015 Mw 7.8 Gorkha, Nepal, earthquake occurred in the central Himalayan collisional orogenic belt, which demonstrated complex fault kinematics and significant surface deformation. The coseismic deformation has been well documented by previous studies using Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) data. However, due to some limitations of spatially sparse GPS stations and InSAR only-one-dimensional observation in the line-of-sight (LOS) direction, the complete distribution and detailed spatial variation of the three-dimensional surface deformation field are still not fully understood. In this study, we reconstructed the three-dimensional coseismic deformation fields using multi-view InSAR observations and investigated the refined surface deformation characteristics during this event. We firstly obtained four ascending and descending InSAR coseismic deformation maps from both Sentinel-1A/B and ALOS-2 data. Secondly, we obtained the synthetic north-south deformation field from our best-fitting slip distribution inversions. Finally, we calculated three-dimensional deformation fields, which were consistent with coseismic GPS displacements but with higher resolution. We found that the surface deformation is dominated by horizontal southward motion and vertical uplift and subsidence, with minor east-west deformation. In the north-south direction, the whole deformation area reaches at least 150 × 150 km with a maximum displacement of ~1.5 m. In the vertical direction, two areas, including uplift in the south and subsidence in the north, are mapped with a peak displacement of 1.5 and −1.0 m, respectively. East-west deformation presented a four-quadrant distribution with a maximum displacement of ~0.6 m. Complex thrusting movement occurred on the seismogenic fault; overall, there was southward push motion and wave-shaped fold motion.

scholarly journals Coseismic deformation field derived from Sentinel-1A data and slip inversion of the 2015 Chile Mw8.3 earthquake

2016 ◽  
Author(s):  
Ronghu Zuo ◽  
Chunyan Qu ◽  
XinJian Shan ◽  
Yingfeng Zhang ◽  
Guohong Zhang ◽  
...  
Keyword(s):  
Surface Deformation ◽  
Joint Inversion ◽  
Fault Slip ◽  
Deformation Field ◽  
Seismogenic Zone ◽  
Coseismic Deformation ◽  
Dislocation Model ◽  
Coulomb Stress ◽  
Coseismic Slip ◽  
Single Plane

Abstract. We obtain the coseismic surface deformation fields caused by the Chile Mw8.3 earthquake on 16 September 2015 through analyzing Sentinel-1A/IW InSAR data from ascending and descending tracks. The results show that the main deformation field looks like a half circle convex to east with maximum coseismic displacement of about 1.33 m in descending LOS direction, 1.32 m in ascending LOS direction. Based on an elastic dislocation model in a homogeneous elastic half space, we construct a small-dip single plane fault model and invert the coseismic fault slip using ascending and descending Sentinel-1A/IW data separately and jointly. The results show that the patterns of the main slip region are similar in all datasets, but the scale of slip from ascending inversion is relatively smaller. Joint inversion can display comprehensive fault slip. The seismic moment magnitude from the joint inversion is Mw8.25, the rupture length along strike is about 340 km with a maximum slip of 8.16 m near the trench located at –31.04 N, –72.49 E, and the coseismic slip mainly concentrates at shallow depth above the hypocenter with a symmetry shape. The depth where coseismic slip is near zero appears to a depth of 50 km, quantitatively indicating the down-dip limit of the seismogenic zone. From the calculated coseismic Coulomb stress change, we find aftershocks locations correlate well with the areas having increased Coulomb stress and most areas with increased Coulomb stress appeared beneath the main shock fault plane.

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